The present invention relates to telecommunications systems and, in particular, to an improved system and method for user presence.
Modern messaging systems, such as those based on the Session Initiation Protocol (SIP), provide presence capabilities, particularly in association with Instant Messaging systems. In presence server systems, a user typically maintains a buddy list or contact list of persons for whom presence information is desired. The presence server system in turn maintains one or more watcher lists of those who are watching a particular user and to whom that user's presence information is sent. When a user A logs in, a presence server identifies the logged in user as present and transmits the information to users on the watcher list of user A. The active users can then exchange instant messages with user A, and the like.
In order to update presence status in users' watcher lists, such systems, however, are dependent upon users logging into, and being logged in to, the system. If a user who is not logged in is listed on an active user's watcher list, an indication can be made on the active user's watcher list that the not logged-in user is not active. However, the presence status of the user is not updated until the user logs in, even if the not logged-in user is present, but engaged in another task not involving the system.
As such, there is a need for a system and method for more effectively providing presence information. There is a further need for a system and method for providing presence information for users who are not logged in to a presence system.